[Elecraft] AE4PB at carolinaheli.com

Bob McGraw K4TAX rmcgraw at blomand.net
Tue Mar 31 15:30:13 EDT 2020


Yes correct.  However as one will reduce the loss in the CATV coax and 
will likely increase the loss in the matching network at the base of the 
antenna.  The mismatch loss in the CATV coax is 0.205 dB, based on 
earlier calculations.   I would question the loss in a broadband network 
to be less.

73

Bob, K4TAX


On 3/31/2020 2:21 PM, John Kosko wrote:
> The response from K4TAX was fine if you’re willing to settle for >2:1 SWR at the antenna.  If you want a better match, consult the book, “Understanding, Building and Using Baluns and Ununs” – Jerry Sevick W2FMI, which is/was available at the ARRL store.  I have a copy and found page 92 talks about building a 2:1 Unun for 32Ohms to 50Ohms and the same design can also match 50Ohms to 75Ohms.  Note that the ratio 32 Ohms to 75 Ohms is not quite what this Unun is supposed to perform…but it’s close.  Efficiency into 50Ohms is purported to be 97-99% over 1 to 30 MHz.   Also note that baluns like to work into a non-reactive load.  73
>
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